Method and device for avoiding macro interference

Abstract

Provided are a method and a device for avoiding interference of an uplink in a macro cell within a heterogeneous cellular network system. A femtocell base station calculates a degree of the interference of the uplink in the macro cell, and determines whether the interference is strong. If the interference of the uplink in the macro cell is strong, the femtocell base station changes the order of a femtocell uplink frame and a femtocell downlink frame.

The invention claimed is: 
     
       1. A communication method of a femtocell base station, the method comprising:
 determining whether an operation is to be performed by switching ordinal positions of a femtocell uplink frame and a femtocell downlink frame in a femtocell based on a degree to which macro uplink interference affects a performance of the femtocell in the femtocell base station; 
 receiving, from a macrocell base station, a request to relay macrodata to be transmitted from a macrocell terminal to the macrocell base station; 
 receiving the macrodata from the macrocell terminal; 
 processing a transmission of the femtocell uplink frame based on the switched ordinal positions; 
 processing a transmission of the femtocell downlink frame based on the switched ordinal positions; and 
 transmitting the macrodata to the macrocell base station, 
 wherein the processing of the transmission of the femtocell downlink frame and the transmitting of the macrodata to the macrocell base station are concurrently performed based on a superposition coding scheme. 
 
     
     
       2. The method of  claim 1 , wherein the determining comprises calculating the degree based on a reception signal-to-noise ratio (SNR) for each point in time within a predetermined time interval. 
     
     
       3. The method of  claim 1 , wherein the determining comprises determining whether a gain of the performance is achieved by switching the ordinal positions of the femtocell uplink frame and the femtocell downlink frame. 
     
     
       4. The method of  claim 3 , further comprising:
 transmitting a request for information associated with a macrocell terminal to a macrocell base station; and 
 receiving a response to the request from the macrocell base station. 
 
     
     
       5. The method of  claim 1 , further comprising:
 transmitting, to a macrocell base station, information on whether the ordinal positions of the femtocell uplink frame and the femtocell downlink frame are switched. 
 
     
     
       6. The method of  claim 1 , wherein the femtocell uplink frame comprises femtocell uplink data transmitted from a femtocell terminal to the femtocell base station, and the femtocell downlink frame comprises femtocell downlink data transmitted from the femtocell base station to the femtocell terminal. 
     
     
       7. The method of  claim 1 , wherein the transmission of the femtocell uplink frame based on the switched ordinal positions is performed during a process of transmitting a macrocell downlink frame in a macrocell base station, and the transmission of the femtocell downlink frame based on the switched ordinal positions is performed during a process of transmitting a macrocell uplink frame in the macrocell base station. 
     
     
       8. A femtocell base station comprising:
 a processor to determine whether an operation is to be performed by switching ordinal positions of a femtocell uplink frame and a femtocell downlink frame in a femtocell based on a degree to which macro uplink interference affects a performance of the femtocell in the femtocell base station; and 
 a networking device to process a transmission of the femtocell uplink frame and a transmission of the femtocell downlink frame based on the switched ordinal positions, 
 wherein the networking device receives from a macrocell base station a request to relay macrodata to be transmitted from a macro terminal to the macrocell based station, receives the macrodata from the macrocell terminal, and transmits the macrodata to the macrocell base station, 
 wherein the processor transmits the macrodata to the macrocell base station while processing the transmitting of the femtocell downlink frame concurrently by controlling the networking device based on a superposition coding scheme. 
 
     
     
       9. A communication method of a macrocell base station, the method comprising:
 receiving information on whether ordinal positions of a femtocell uplink frame and a femtocell downlink frame are switched, from each of a plurality of femtocell base stations; 
 selecting one of femtocell base stations transmitting the information among the plurality of femtocell base stations, as a relay femtocell base station to relay macrodata; 
 transmitting the request to the relay femtocell base station; and 
 transmitting information associated with the relay femtocell base station to a macrocell terminal, 
 wherein the macrodata is data to be transmitted from the macro terminal to the macrocell base station, 
 wherein the relay femtocell base station is a femtocell base station corresponding to a maximum singal-to-noise (SNR) among SNRs of the macrocell base station to each of femtocell base stations transmitted the information indicating that the ordinal positions of the femtocell uplink frame and the femtocell downlink frame are switched. 
 
     
     
       10. A macrocell base station comprising:
 a networking device to receive information on whether ordinal positions of a femtocell uplink frame and a femtocell downlink frame are switched, from each of a plurality of femtocell base stations; and 
 a processor to select one of femtocell base stations transmitting the information among the plurality of femtocell base stations, as a relay femtocell base station to relay macrodata, 
 wherein the networking device transmits a request to relay the macrodata to the relay femtocell base station and transmits information associated with the relay femtocell base station to a macrocell terminal, 
 wherein the macrodata is data to be transmitted from the macro terminal to the macrocell base station, and 
 wherein the relay femtocell base station is a femtocell base station corresponding to a maximum signal-to-noise (SNR) among SNRs of the macrocell base station to each of femtocell base stations transmitted the information indicating that the ordinal positions of the femtocell uplink frame and the femtocell downlink frame are switched.